Ringing Sound When Accelerating

[Perlova]

My 2005 OutBack 2.5i is prone to making a ringing(pinging, vibrating?) sound when I am accelerating. It is very annoying and makes me think that I am driving a sewing machine. The dealer can't find the source of the moise although they admit to hearing it.
Has anyone else had this issue? It did not exist in any of the demo cars that I have driven.

[BlueRoo'02]

If you're talking about a high pitched whistle like sound replicated only under full throttle then it is likely the exhaust system to blame for that. I've had that with 2 of the Outbacks I have owned. Usually shows up somewhere around 70-80,000 miles for me anyway. In my experience a good muffler shop was the only place to find satisfaction... the dealers don't seem to understand this for some reason.

[Perlova]

No , it's more like a stuttered ring. Not a whistle. It's more pronounced when the engine is cold. Almost like a dieseling sound and it occurs at all RPM's during acceleration.

I have had it in the shop several times, so far they can't find it although they admit it is a problem. The car is at the dealers right now waiting for a regional service rep from Subaru to look at it. The dealer thinks it might be "piston slap" (whatever that is...)

Roman

[4Wheel]

"Piston slap" THe skirts of the pistons are worn enough to allow the piston "rock" on the wrist pin creating a rattling noise that can sound like a "diesel ignition" ping. The Subaru's have this as a known issue. Regular oil changes with a quality oil.

[intel_guy]

I believe I have a similar noise in my 02 outback. If I put the trans in N when moving the noise goes completely away at all RPMs. Looks like a transmission noise to me.